The EX1 drive train was designed specifically for the demands of electric-assist mountain bikes: a wide gear range with bigger jumps between gears and sturdy components to handle higher torque loads. Liberal use of features found on SRAMa (TM)s high end MTB parts provide high value, quiet operation and ease of service.Dual position clamp attachment gives riders fitting optionsCable pull ratio matches the EX1 cassette and derailleur